The present invention relates to a document recycling copier and, more particularly, to a document recycling copier of the type having, in a system configuration, a copier body, a recycling document handler which may be loaded with a stack of documents of different sizes, and a finisher for automatically arranging and binding a sequence of copied paper sheets. The copier with which the present invention is concerned is capable of copying documents of different sizes on paper sheets which individually match the documents in size, or copying all of them on paper sheets of a single size, as desired.
A current trend in the copiers art is toward a multi-function and systematic configuration which includes an automatic document feeder (ADF). An advanced type of ADF available today is a recycling document handler (RDH) having a document tray which may be loaded with a stack of documents of different sizes randomly. The RDH sequentially transports such documents one by one from the tray to an exposing station defined on a copier body while returning them to their predetermined position on the tray. Further, a copier with an RDH is operable with a finisher which automatically arranges and binds copied paper sheets which sequentially come out of the copier. With the combination of a copier, RDH and finisher, therefore, it is possible to automatically produce a desired number of bound sets of copies each consisting of reproductions of a sequence of documents simply by stacking the documents on the tray of RDH and then pressing a print key of the copier.
A problem with the prior art copier is that a stack of documents of different sizes cannot be reproduced without lowering the copying efficiency to a critical extent. Specifically, the sizes of the individual documents have to be sensed at each time of copying so as to select paper sheets of a size which match a particular document size each time. Further, when paper sheets of a particular size are selected beforehand, optics of the copier have to be moved to select an adequate magnification each time. A copier may be provided with an RDH constructed such that a stack of documents of different sizes laid on the tray are sequentially transported toward a glass platen of a copier body, the lowermost document being first, while being squentially returned to the tray after imagewise exposure, as disclosed in Japanese Laid-Open Patent Publication (Kokai) No. 61-263534 by way of example. The copier disclosed in this Laid-Open Patent Publication has a capability for steering a copied paper sheet which carries an image on one side thereof, i.e., one-sided copy to return it toward a copy processing section of the copier body for thereby automatically producing a two-sided copy. This kind of copier has document size sensing means for sensing the sizes of individual documents while the documents are sequentially fed from the tray, document size sensing means for sequentially memorizing the sensed document sizes while the documents are circulated once prior to the start of actual copying operations, and means for sequentially reading the document sizes out of the storing means to group the documents on a size basis. While such a copier is capable of reproducing documents belonging to a particular size group on paper sheets which have the same size as the documents, it cannot reproduce all the documents of different sizes on paper sheets of a single size with high efficiency.
Another problem with a prior art copier having an RDH and a finisher is that when documents of different sizes are to be stacked on the tray of the RDH to be copied size by size and then automatically bound by the finisher, one has to rearrange the documents on a size basis before actually operating the copier. In addition, when bound sets of copies which are different in size from each other are driven out of the finisher onto a discharge tray randomly, it may occur that a larger set of copies is laid on a smaller set of copies. This not only prevents the bindings from being stacked neatly on the discharge tray but also makes it difficult for one to see the underlying bindings.